With rapid development of computer and communication technologies, using a public packet-based network to bear voice, data, images and other various services becomes a direction of the network development. The trend of service development and network convergence gives rise to Next Generation Network (NGN), which is centered on soft-switch device. The NGN works in a packet-based network, and uses a distributed network architecture. It bears voice, video and multimedia services effectively, and achieves separation of the service application, service control, and service transmission. An NGN in the prior art includes a Media Gateway (MG) and a Media Gateway Controller (MGC). The MGC is configured to manage call state and control bearer resources of the MG. The MG is configured to convert the format of media flows. For example, the MG converts the media information in the E1 timeslot in a Circuit Switched (CS) network into Realtime Transport Protocol (RTP) media flows of an Internet Protocol (IP) network. Moreover, the MG creates, modifies, and releases media flows, and manages resources under signaling controlling of the MGC.
The popularization of the NGN increases the demand for IP addresses massively. Currently, two solutions to coping with deficiency of IP addresses are: deploying IPv6 addresses uniformly, and applying the NAT traversal technology. The IPv6 brings revolutionary transformation to the existing network. Deployment IPv6 addresses is a focus in the next stage of implementing the NGN. Therefore, for the current stage of deploying the NGN, importance should be attached to the NAT traversal technology.
The MG implements NAT functions. When the MG is located between a private network and a public network, address mapping is generated on the MG when the MG receives an IP packet sent by the private network to the public network.
In the process of developing the present invention, the inventor finds at least the following problems in the prior art:
In the prior art, the NAT address mapping table tends to be oversized, for example, includes 100,000 NAT address mapping entries. Therefore, the maintenance of the NAT address mapping is essential. However, in the prior art, the MGC and the MG are unable to operate the NAT address mapping table.